1. Field
The present disclosure generally relates to wireless power transmission devices and related methods. More specifically, particular embodiments relate to devices and methods for selectively controlling a plurality of power transmission coils in a wireless power transmission device.
2. Description of Related Art
Generally, a battery pack stores electric power received from an external charging device and supplies the stored electric power to a portable device such as a cellular phone or Personal Digital Assistant (PDA) for its operation. The battery pack includes a battery cell for storing the electric power and a circuit for charging and discharging the battery cell for, for example, supplying the electric power to the portable device. To connect the charging device to the battery pack for charging, the charging device, which receives electric power from a general power source (e.g., household power outlet or car charger plug) and converts the electric power to appropriate voltage and current corresponding to the battery pack, may use a port connector to connect to a port or terminal of the battery pack to supply the electric power.
Such a connection method, however, may cause instantaneous discharge when the charging device and the battery pack make contact with or are separated from each other because the terminals in both sides of the battery pack and the charging device have a different electrical potential. The instantaneous discharge may also cause a fire when foreign substances are accumulated in the terminals.
Moreover, the electric power stored in the battery pack may be self-discharged due to moisture in the surrounding atmosphere via the terminal of the battery pack. This self-discharge may cause a reduction of an operational life and a deterioration of a performance of the battery pack.